Pseudofossil (?) From Death Valley

[Natalie]

Hi everyone, this is my first post here. About four or five years ago I was in the Mojave Desert, and I found an interesting rock in a wash that looks like a fossil to me. I've been wondering about it ever since I found it, but I just now thought of asking people online. I did read the sticky about people posting pictures of "interesting rocks", and after doing plenty of research, I am still not sure about this rock.

I'm not exactly sure if the matrix is a metamorphic or a sedimentary rock (I can't find any pictures that look like it online). The "bone" is a few inches long and is made of a different type of rock I believe. It appears to have almost a spongy texture on the outside, but is solid inside. It sticks out from the matrix, I would assume because of weathering and erosion. On the back of the rock is another type of mineral, which is whitish and very rough/bumpy. I have no idea what type it is or how it formed.

I was hoping someone on here might be able to tell me once and for all if it's a fossil or not. I got a few pictures of it, but if anyone wants to see another part of the rock in detail I'd be glad to take some more. Thanks in advance for any help!

[jpbowden]

I don't know what it is but it is a keeper, I love stuff like that.

[Terry Dactyll]

Natalie....... I wont profess to know anything about rocks but It looked to me at first like the 'bone' is infact a mineral infill running across like other white viens inside the rock.... sometimes during its settlement the matrix has cracked which allowed consentrations of minerals to form crystals and infill the void over time.... Sometimes this mineral is of a higher hardness value than the surrounding matrix hence it resists natural erosion more and begins to stand proud...... The only thing that goes against this theory is the other 'mineral veins' should be standing proud to......Im sure theres someone with a better theory, good luck......

[Natalie]

Thanks for the replies!

Would the "bone" (for lack of a better term) have formed before or after the white veins in the rock? Is there a way to tell if the matrix is sedimentary or metamorphic? The "bone" does have many small cracks in it, but there doesn't appear to be any of the white crystalline mineral in them. The mineral in the veins does stick up some, but not as much as the mineral that the "bone" is made from.

I think the "bone" was at one time longer than it is now, on the end where it intersects the largest white vein. At some point in time the "bone"/mineral inclusion appears to have broken in two, but the two parts remained close together, separated only by the white vein. I thought of that when I was taking some more photos of it and I noticed that the white vein on the opposite side of the "bone" has an outline where it looks like another piece should be but broke off.

Here are a few more photos of the rock:

[RJB]

Boy,, thats a tuff one! Im not going to say it 'isnt' a fossil, but it would help if you knew formation that you found it in. Looks like some very ancient rock

RB

[Natalie]

Haha, how ancient is ancient?

I was in high school during the trip where I found this rock, and I can't quite remember exactly where it was, but I remember it wasn't too far a drive (30-40 minutes) from the Ubehebe Craters if that's any help. I was camping near a small wash and the rock was just laying there among the rubble.

What exactly do you mean by formation? Is that like the type of rock it was found in or the precise location or something along those lines? Sorry, I'm just a casual rock/fossil collector and I'm still trying to learn the lingo.

[tracer]

there isn't enough information/context associated with your specimen for us to accurately and with confidence state much about it. the "bone" looking thing does not appear to be bone, and therefore is likely to have been a mineral infilling of a void. the shape of it connotes a burrow, but not definitively enough to state that it was one, particularly in the absence of context of other rocks nearby. the dark matrix and the white material in the cracks is very likely to have been sedimentary in nature, but i really can't see it closely enough to say for sure whether it's something like lithified mud or shale with gypsum evaporite in the cracks, or even an igneous basaltic-type matrix with quartz in it. i trend toward believing the former, particularly with the long, flat shape of the thing implying that it was laid down as a layer.

but the main problem is lack of context. when you say you found it in the mojave desert, there's no real frame of reference, in that the mojave has all kinds of different geology associated with it. best to do some independent reading on the basics and begin to tentatively identify geologic areas and formations, so you can learn to recognize some of the stuff by where it's found and what's around it.

mojave geology basics

best regards

[Natalie]

Thanks for the link! I didn't realize the Mojave Desert's geology was that complex, I apologise for not knowing more precisely where I found the rock. I'll keep searching on Google Earth for the area based on what I remember it looking like, but I don't know how accurate that might be.

Here are some closer shots of the matrix/veins: